Conventional semiconductor-based, micro-strip and waveguide combiners have been used to generate, e.g., microwave power by combining the outputs of a plurality of energy sources. With small scale or size, and high reliability characteristics, micro-strip-based combiners have been used to combine a plurality of low power signals to output a high power signal. Similarly, interchangeable transmission lines have been used in, e.g., tree configurations, to combine a plurality of low power signals to output a high power signal.
Micro-strip-based combiners, for example, which tend to be the most common combiners, suffer from high combining losses, especially in the millimeter-wave frequencies, and limited power handling, and, as a result, are limited with the number of resources that can be combined.
Waveguide combiners can handle significantly higher power than semiconductor-based combiners. However, waveguide combiners frequently can become too large, too heavy and too expensive, especially at low microwave frequencies. While there is no limit to the number of energy source outputs that may be combined in waveguide combiners, the size, weight, and cost of the waveguide combiner goes up with the number of energy source outputs. They can also have bandwidth limitations.
Recently, new techniques of quasi-optical and spatial power combiners have been used in waveguides and coaxial forms of combiners. Rectangular waveguide spatial combiners can handle high power microwave levels, but these combiners suffer from limited bandwidth, as well as from a limited number of combined transistors (especially in the millimeter-wave frequencies), and from non-uniform illumination of a loaded finline array inside the waveguide. Coaxial spatial combiners have the bandwidth capability, but these combiners tend to have complex constructions that are difficult to fabricate and, therefore, may not be applicable for millimeter-wave applications. Moreover, it is almost impossible to remove heat efficiently from the loaded finline array.
The present disclosure provides a compact, buildable, substantially planar, solid-state, high power, wideband, low-loss combiner that has superior thermal management.